Lighting for the filament of a lightbulb
Probably best to understand that the “white” in the core you are used to seeing isn’t “white” in most instances, but rather a particular colour.

We have grown to think that there is “white” at the core of many high emission objects due to learned aesthetics that largely stem from photographs. Candles, which are distinctly orangey, fires, the sun, etc. are all captured on film as blown out, which after adaptation, is a neutral white.

In raytracing, if you use a decent camera rendering transform, you can lean on it to generate exactly what you are hoping for. A wonderful example here is from Tynaud’s neon demonstration.



As you can see, the colour emitted is a rather saturated blue, yet the core naturally overexposes to a blown out white.

Lean on a good camera rendering transform and have your emission high enough.